CHAPTER VIII.

FROM GALILEI TO NEWTON (FROM ABOUT 1638 A.D. TO ABOUT 1687 A.D.), §§ 152-163 198-209

§ 152. The general character of astronomical progress during the period 198

§ 153. Scheiner’s observations of _faculae_ on the sun. _Hevel_: his _Selenographia_ and his writings on comets: his star catalogue. _Riccioli’s New Almagest_ 198

§ 154. Planetary observations; _Huygens’s_ discovery of a satellite of Saturn and of its ring 199

§ 155. _Gascoigne’s_ and _Auzout’s_ invention of the _micrometer_: _Picard’s_ telescopic “sights” 202

§ 156. _Horrocks_: extension of Kepler’s theory to the moon: observation of a transit of Venus 202

§§ 157-8. Huygens’s rediscovery of the pendulum clock: his theory of circular motion 203

§ 159. Measurements of the earth by _Snell_, _Norwood_, and Picard 204

§ 160. The Paris Observatory: _Domenico Cassini_: his discoveries of four new satellites of Saturn: his other work 204

§ 161. _Richer’s_ expedition to Cayenne: pendulum observations: observations of Mars in opposition: _horizontal parallax_: _annual_ or _stellar parallax_ 205

§ 162. _Roemer_ and the velocity of light 208

§ 163. _Descartes_ 208